Meanwhile, some airlines and the media are after a scapegoat and they've found a totally innocent one: Met office blamed for unnecessary six-day closure - complete nonsense of course since the Met Office were simply passing on direct observations of actual volcanic ash, and predictions (which proved very accurate as it happens) as to where the ash would spread. They're as guilty for this as they are for the Cumbrian floods last October.

The decision was based on a computer model operated by the Meteorological Office's Volcanic Ash Advisory Centre, which suggested there was a cloud of ash covering northern Europe. This prompted a warning from the Met Office, which triggered the wider European ban, via Eurocontrol, the Brussels-based air traffic control centre. However, the model is no more than that - a mathematical model. There was no empirical evidence to back up its findings.

Eruptions from the Eyjafjallajökull volcano are weaker than they were at the weekend but eruptions still take ash over 10,000ft at times. Weather patterns continue to blow areas of ash towards the UK.

The Met Office is the North-west European Volcanic Ash Advisory Centre with responsibility for issuing the Volcanic Ash Advisories for volcanoes erupting in this area. This means the Met Office's priority and role is to support NATS, CAA and other aviation authorities decision-making.

It is for the aviation industry and regulator to set thresholds for safe ash ingestion. Currently, world-wide advice from ICAO is based on engine and airframe manufacturers stating that aircraft should not be exposed to any volcanic ash.

Met Office and NERC observations are consistent with Met Office model forecasts for spread of ash over UK and north-west Europe and NATS are continuing to advise restrictions on UK airspace until Tuesday morning.

As the volcanic activity changes, there may be some clearance of ash at times, over parts of the UK. We will be looking to provide timely advice about when these opportunities might happen.

The Met Office is unable to advise of any details of any flights. However, many airlines are providing information on their websites.

I can feel them biting their tongue ...... Incidently, the MetO also provide actual dust observations from across the UK (note many of these are from RAF bases), as well as satellite images. There's also been use of ground based LIDAR. And elsewhere in Europe, Swiss lasers map volcanic ash cloud from Iceland. Though I'm sure there are many who'll still happily believe the MetO have made it all up.

I think the most pertinent comment I've seen comes from the EU director general of transport, Matthias Ruete who is reported as saying “We don’t even know what density the cloud should be in order to affect jet engines." Exactly! And whose fault is that? Not the UK Met Office VAAC that's for sure! The simple fact is that the airline industry provides no data on what concentratins of ash their aircraft can fly through, therefore it has to be assumed that all concentrations are dangerous - until proven otherwise. The airline industry has made a right mess of things are and desperately thrashing about in their own shit looking for someone, anyone, else to blame. And meanwhile, they are oddly quiet about the damage caused to those Finnish air force jets ..... Or, indeed this other presumably fictional case of F-16 fighters damaged by volcanic ash.

And while all this has been going on, the rest of the world seems to have been very quiet weatherwise ...... though the heatwave continues unabated in India. So just a few other stories to bring today:

** Edit: latest update, clearly written to reinforce the facts, in light of some false media stories:

Science underpins ash cloud advice

Last updated: 1541 BST on Tuesday, 20 April 2010

Eruptions from Eyjafjallajökull have continued overnight with debris being emitted up to 4 to 5 km for much of the time. Weather patterns continue to blow areas of ash towards the UK.

The Met Office uses multiple dispersion models endorsed by the international meteorological community. The output from the Met Office volcanic ash dispersion model has been compared with our neighbouring VAACs in Canada and France since the beginning of this incident and the results are consistent.

Our models are confirmed by observations which have seen ash in the UK and south of England. These include:

Multiple land observations have recorded ash in the skies across the UK, including across southern Britain.

Balloon observations have shown a 600 m deep ash cloud at an altitude of 4 km across parts of the UK.

The Met Office is the north-west European Volcanic Ash Advisory Centre with responsibility for issuing the Volcanic Ash Advisories for volcanoes erupting in this area in line with internationally agreed standards and processes. This means the Met Office’s role is to support NATS, CAA and other aviation authorities decision-making.

It is for the aviation industry and regulator to set thresholds for safe ash ingestion. Currently, world-wide advice from ICAO is based on engine and airframe manufacturers stating a zero tolerance to ash ingestion. This means that aircraft should not be exposed to any volcanic ash.

The idea of this blog is to produce a regular round up of global weather and related news stories which then acts as an archive. Some links may be lost in time but by searching the original headline on Google it should be possible to find related stories. Additionally, it gives me somewhere to add my own thoughts on some stories, as the mood takes me.